This invention relates to volatile food flavoring compounds such as flavors, flavor enhancers, aromas, and aroma enhancers, and more particularly to volatile flavoring compounds such as acetaldehyde, fixed in crystalline food materials such as sucrose to form solid flavoring compositions which are stable under normal shelf storage conditions, but which release flavoring when combined with either hot or cold water.
It has been known for some time that flavoring compounds such as acetaldehyde are important flavor components of natural fruits and vegetables and serve as flavor enhancers for the various flavor notes naturally present in meats, fruits and vegetables. Particularly, it has been found that acetaldehyde is very important in increasing the impact and freshness of certain flavors, such as fruit-type flavors. However, while the presence of acetaldehyde would be a valuable enhancer to a synthetic flavoring composition for use with a food formulation employing fruity-type flavors, it is difficult to incorporate acetaldehyde into a stable, solid flavor fixative. Most attempts to fix acetaldehyde in various compositions have tended to be unstable in the presence of small amounts of water or water vapor. This stability problem was apparent when powdered dessert and beverage products containing the fixed acetaldehyde were processed or packaged in a manner allowing atmospheric or product moisture to reach the fixed acetaldehyde during storage of the product. This problem is particularly acute when a fruit-type dessert or beverage formulation using a fixed acetaldehyde flavor is packaged in dry form in a non-hermetically sealed paper envelope or container which is sufficiently pervious to allow atmospheric moisture to enter and release acetaldehyde.
Acetaldehyde is chemically very reactive; it is very soluble in water; and it has a low boiling point (21.degree.C). It exists as a gas at normal room temperature and pressure. It, furthermore, is readily oxidized to form acetic acid, and it easily polymerizes to form paraldehyde and metaldehyde. Thus, the problem confronting the food industry in augmention the flavor and aroma of dry powdered mixes has been that of "fixing" acetaldehyde in a sufficiently stable state to avoid volatization and/or chemical reaction during storage. It also is necessary to limit the degree of fixation to permit the release of the acetaldehyde compound during the normal household preparation of rehydrating or otherwise preparing a finished table product from the powdered mix (e.g. by addition of either hot or cold water).
Generally speaking, there are two methods of "fixing" acetaldehyde to insure improvement in shelf stability. One method is to chemically react the acetaldehyde with another material to form a more stable compound. The second method is to physically entrap or coat the acetaldehyde with a stable compound such as sugar, gum or other edible material.
With respect to the first method -- that of forming a more stable compound -- the resulting composition must not only have a degree of stability and dissociability compatible with storage and subsequent use conditions, but it must also be a functional derivative type compound; that is, it must have an inherent chemical structure which will release acetaldehyde upon decomposition. Also the residual decomposition compound other than the acetaldehyde resulting from the breakdown of the functional derivative compound must not be detrimental to the quality of the finished food product. It is also essential that the breakdown take place under the conditions at which the food product is prepared or used.
Although many attempts, such as U.S. Pat. No. 2,305,621, have been made to produce suitable functional derivative compounds by reacting acetaldehyde with other chemical compounds, with few exceptions, they have not resulted in operational successes. The major causes of the failures have been instability of the resulting product or, conversely, too great a stability to provide utility.
The second method of physically encapsulating the acetaldehyde within a stable compound has not usually met with commercial success since the products prepared by this method have been in a glassy or amorphous state and have tended to lose their fixed flavor during storage especially in the presence of moisture.
A recently issued U.S. Pat. No. 3,314,803 to Dame, et al., discloses a method of fixing acetaldehyde by encapsulating the acetaldehyde in a matrix of dry mannitol. This procedure has produced a dry, non-hygroscopic material which will retain a portion of its fixed acetaldehyde even under non-hermetic conditions, but has the disadvantage of being very costly because of the current price of mannitol. The spray-dried, mannitol-acetaldehyde composition of Dame, et al., can have an initial fixation of 2% to 10% by weight of acetaldehyde. However, this initial fix will be modulated in several days and the level of acetaldehyde will equilibrate to a stable range usually between 1% to 3%.
Generally, the prior art has indicated that in order to preserve flavor materials out of contact with the atmosphere, fixation should be achieved by means of amorphous matrix material. U.S. Pat. No. 2,856,291 to Schultz discloses that crystallization should be avoided since the crystal structure will enable the escape of the flavor materials or the permeation of the atmosphere into the flavoring composition through the interstices of the crystal structure. The Dame, et al., patent discloses encapsulating the acetaldehyde within the mannitol matrix without crystallizing the mannitol.